Satellite phone

A satellite phone, often called a satphone, is a mobile device that connects to the public switched telephone network. Instead of using terrestrial cell sites, which are ground-based towers, these phones communicate through orbiting satellites. This technology is vital because it provides connectivity in areas where traditional network coverage is unavailable or has been disrupted.

They are frequently used for maritime and aviation communication, remote expeditions, mining, and emergency response. Most of these devices support voice calls, text messages, and low-bandwidth data services.

The mechanism of a satellite phone depends on maintaining a line-of-sight to a satellite in space. When a user makes a call, the signal travels from the handset to a satellite orbiting the Earth. This satellite then relays the signal back to a ground station or network. Because the connection relies on space-based hardware, indoor reception is often limited. Users may need to use external antennas or repeaters to improve their signal.

While early handsets were large and required deployable antennas, modern models are much smaller. Some are now comparable in size to ordinary smartphones.

Satellite telephony systems generally operate using two distinct types of orbital paths. The first is geostationary orbit, known as GEO. These satellites orbit at a high altitude and appear to stay in a fixed spot in the sky. This allows a few satellites to provide near-global coverage. However, the long signal path introduces latency, which is a delay in communication. GEO service is reliable up to roughly 70 degrees latitude, but signal quality may drop near the poles.

The second type is low Earth orbit, or LEO. These satellites orbit much closer to Earth and move very quickly. They complete an entire orbit every 70 to 100 minutes. Because each satellite is only visible from a specific location for a few minutes, a large group is required. This group is called a constellation. For example, the Iridium network uses 66 active satellites near the poles to provide global coverage. The Globalstar network uses 48 active satellites to cover most land areas.

The history of this technology began shortly after the launch of Sputnik 1. In 1958, the experimental SCORE satellite transmitted the first voice signals via satellite. Later, in 1963, Prime Minister Abubakar Tafawa Balewa used a SYNCOM satellite to speak with President John F. Kennedy.

In 1976, MARISAT became the first dedicated mobile communications satellite. This was later integrated into Inmarsat, an organization founded in 1979. Many major LEO operators, including Iridium and Globalstar, launched in the late 1990s.

Using satellite phones can be significantly more expensive than using standard cellular service. This is due to the high costs of launching and maintaining satellites in space. Handsets typically cost a few hundred US dollars, while new broadband terminals can cost several thousand. Service fees often include a monthly base charge and per-minute rates that are higher than cellular equivalents. Furthermore, some governments, such as China, India, and Russia, place legal restrictions on these devices. They often cite concerns regarding national security or spectrum management.

In recent years, satellite technology has begun to merge with everyday consumer electronics. In 2022, Apple introduced emergency satellite messaging with the iPhone 14. The iPhone 15 expanded this in 2023 by adding roadside assistance. Other manufacturers have followed suit, such as Huawei with the Mate 50 series and Xiaomi with the 14 Pro Titanium Edition.

Some specialized devices, like the 2024 Thuraya Skyphone, even feature massive retractable antennas. These advancements allow standard smartphones to access life-saving communication in areas lacking terrestrial towers.